Which of the following statements are correct when a mixture of NaCl and K2 Cr2 O7 is gently war

step 1 This is a test called chromyl chloride test. Chromyl chloride test. So in chromil chloride test,

Which of the following statements are correct when a mixture...

Which of the following statements are correct when a mixture of $\mathrm{NaCl}$ and $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ is gently warmed with conc. $\mathrm{H}_{2} \mathrm{SO}_{4}$ ?(a). A deep red vapour is evolved (b) The vapour when passed into $\mathrm{NaOH}$ solution gives a yellow solution of $\mathrm{Na}_{2} \mathrm{CrO}_{4}$ (c) Chlorine gas is evolved (d) Chromyl chloride is formed

Which of the following statements are correct when a mixture of $\mathrm{NaCl}$ and $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ is gently warmed with conc. $\mathrm{H}_{2} \mathrm{SO}_{4}$ ?(a). A deep red vapour is evolved
(b) The vapour when passed into $\mathrm{NaOH}$ solution gives a yellow solution of $\mathrm{Na}_{2} \mathrm{CrO}_{4}$
(c) Chlorine gas is evolved
(d) Chromyl chloride is formed

Key Concepts

Chromyl Chloride Test

This test is a classical qualitative method used to detect chloride ions in a sample. When a chloride-containing compound reacts with a suitable oxidizing agent and a strong acid, a red colored, volatile oxychloride compound is formed. The appearance of the distinctive red vapour is indicative of the presence of chloride, providing a specific and sensitive means for its identification.

Redox Reactions in Acidic Media

In acidic environments, many redox reactions occur between halide ions and oxidizing agents. The strong acid not only supplies the acidic medium but also acts as a dehydrating agent, enabling the formation of volatile oxychloride compounds. These reactions highlight how the oxidation state of elements can change under specific conditions, resulting in products with unique physical properties.

Transformation of Oxychlorides Upon Reaction with Bases

The oxychloride compounds formed in acid react further with basic solutions, such as sodium hydroxide, to yield different ionic species. This transformation, often accompanied by a change in color (for example, turning into a yellow solution due to the formation of chromate ions), is crucial in confirming the identity of the initially formed oxychloride and thus supports the qualitative analysis process.

Transcript

00:02 This is a test called chromyl chloride test.

00:13 Chromyl chloride test.

00:21 So in chromil chloride test, what happens that when k2cr2, that is potassium dichromate, potassium dichromate.

00:53 So, potassium dichromate, this is a strong oxycromate.

00:56 Rising agent right so this potassium dichromate is treated with nacl that is sodium chloride now this sodium chloride is soluble in water right so this is sodium chloride salt and is further treated this mixture right this mixture we have is further treated this mixture of sodium chloride and potassium dichromate is further treated with concentrated hesterosophore.

01:51 H2 .s .4.

01:55 This reaction leads to formation of formation of orange red vapors of chromil chloride.

02:33 So the reaction is as follows.

02:44 Here this is the cl negative ion from nacl.

02:54 This is cr 207 to negative ion from k to cr2 -07.

03:01 This is the h -positive ion from the acid.

03:06 H -124 concentrated and this leads to formation of cro 2 cl2 chromyl chloride and h2 balancing this will be 4 this will be 2 this will be 6 this will be 3 so here these are the chromyl chloride okay so these are in the form of wephers.

03:49 So, these are deep orange red vapors.

04:03 Now these weppers, the weppers of chromile chloride, weppers of chromyl chloride, cro 2, cl2, is then passed into n .o .h.

04:27 Solution, passed into n -a -o -h solution that is sodium hydroxide solution and following this a yellow solution of a yellow solution of sodium chromate is formed sodium chromate is formed so the reaction is as we have cro2 cl2 this is with oh negative so these oh negative ions from n .a .o .h.

05:33 That is sodium hydroxide.

05:35 So this will lead to cro4, 2 negative chromate ions.

05:44 And now cl negative and h2o.

05:52 Balancing, it will be 4 here and it will be here 2.

06:01 And this is also 2.

06:03 So the reaction.

06:04 Is balanced.

06:05 So, because of these chromate ion, okay, because of these chromate ions, we have yellow color.

06:16 So, this is a yellow solution.

06:22 Now, following this, this yellow solution, this yellow solution, this yellow solution of sodium chromate, better say, na2, cro4...